Deep Compositing : How it works in Fusion.
In the informative interviews done by Mike Seymour on FXGuide about deep compositing, he has described examples of fog and candle lights in a row as an explanation of deep composting. These can be achieved in Fusion with the Volume Fog Tool.

The volume Fog tool is a special case render that takes 3D camera and lighting along with ‘deep images’ and renders them out from the cameras point of view.
The ‘Deep Images’ have XY and Z so that it can fit a volume of a 3D scene. The WPP is used to occlude the depth, so beauty passes can be merged into the volume image.
So in Anonymous nonlinear fog volumes of varying density can be integrated with the 3D scene. A rendered beauty pass along with its WPP(RGBA-XYZ) is put into 3D environment of the Volume tool and reacts with the fog volume. Because of the World Position Pass makes a fixed reference in terms of its XYZ coordinates, a Fog volume will stay fixed correctly to the scene. Zbuffer on the other hand is from the cameras rendered point of view, so camera based depth cue fog is not fixed to the scenes point of view.

In Fusion, you can create volumes procedurally using tools like fast noise, or particles, you can also load them via EXR. By doing things procedurally or a mixture of loading and procedurally the amount of data to disk can be dramatically reduced.
In Fusion 6.3, adding lighting models to the Volume Fog tooling, takes what can be achieved in this new deep arena to a whole new level. GPU powering this development makes the Deep Volumes interactive/realtime when rendering.

another mention of fusion on a fxguide article: (stereo conversion by prime focus)

Prime Focus’ View-D system relies on Fusion as its backbone, although the tools have also been ported to Nuke. “The main reason for that is that Fusion is better for handling large amounts of roto splines and polys,” says Baker.

I guess you are right. Although I feel like I should have chosen a less inflammatory title back then, it does reflect the emotional state many of us had when Fusion was practically nowhere to be found on related internet media.

You see Eyeons web site happily display Emmerich talking about his current film White House Down and its "pipeline", but not once mention any Eyeon product.On fxguide they do a fairly in depth article on Emmerich's White House Down and again not one mention of any Eyeon s/w.In fact they mention Nuke, Mari, Flowline, Softimage/ICE, Maya, 3DSMax... everything but Fusion, Generation.

it's silly but i think we're used to THAT, by now.
However to be honest, the interview on Eyeon site - i was so disappointed... for me there was NOTHING worth mentioning...
that "todays software makes making movies better/cheaper".... b..please..
The Anonymous or 2012 were so much better, here there is not even a hint of postproduction in-depth tech.... sad, after watching the video i felt as i lost some time..
But the new promotion makes-up for this
cheers

it's silly but i think we're used to THAT, by now.However to be honest, the interview on Eyeon site - i was so disappointed... for me there was NOTHING worth mentioning...that "todays software makes making movies better/cheaper".... b..please..The Anonymous or 2012 were so much better, here there is not even a hint of postproduction in-depth tech.... sad, after watching the video i felt as i lost some time..